High-speed rail (often abbreviated to "HSR") is a form of rail travel that uses trains that can travel at least 250 km/h (160 mph) on purpose-built tracks. The fastest trains are capable of speeds in excess of 400 km/h (250 mph), though operational top speeds in day-to-day service are often limited to 300 km/h (190 mph) or less. Most definitions also include upgraded legacy tracks if speeds are 200 km/h (120 mph) or higher in revenue service and some high-speed rail services contain no purpose-built tracks whatsoever. Many rail enthusiasts like high-speed trains because of their sleek streamlined designs, which are meant to improve efficiency and reduce air resistance, their eye-catching "snouts" which eliminate the tunnel boom, their modernity and of course their breathtaking speed!

High-speed rail is often faster than flying, if you take into account the time it takes to get to the airport and through security checks, as well as the usually faster boarding procedures for trains. This is particularly true for journeys between relatively nearby cities, and the regions where high-speed rail is most prevalent (western Europe and east Asia) have many large cities in close proximity to one another. A train journey is usually faster than going by plane if it takes three hours or less. And of course, you'll get to enjoy the scenery during your journey, which you generally would not if travelling by plane.

Many high-speed rail services are aimed at business travellers and the fare structure and on-board amenities (e.g. wifi, a place to hang a suit) tend to reflect this.

The vast majority of high-speed trains are electrical multiple units (EMUs), which means they are driven by electricity and have their motive power distributed over most or all of the train instead of concentrated in a single locomotive. This has several technological advantages and means that a design where some passengers sitting directly behind the driver can see the tracks through the front window is easy to implement and has been done on some German ICEs.

Shinkansen 0 series, the world's very first high-speed trains, in service 1964-2008

The first high-speed rail line was Japan's Shinkansen (often called Bullet Train in English; actual translation "new trunk line"), with its first line, the Tōkaidō Shinkansen, completed in 1964 - just in time for that year's Olympic Games in Tokyo. When first completed, it transported passengers between the cities of Tokyo and Osaka in a then-record time of 4 hours, compared to the 6 hours 10 minutes the journey took using conventional railway lines. Since then, technology has improved considerably, with the journey time on the fastest Nozomi trains between Tokyo and Osaka now taking 2 hours 22 minutes, and the operating speed of Shinkansen trains having been increased from 210 km/h (130 mph) when it opened in 1964 to 320 km/h today.

For over a decade, the Shinkansen remained the only high-speed rail network in the world, until the completion of the first line of the Train à Grande Vitesse (TGV) in France in 1981, which broke the Shinkansen's speed record and ushered in a new age of rail travel in Europe. Subsequently, many European countries introduced their own high-speed rail services, the first outside France being Germany's Intercity-Express (ICE) in 1991, which in turn broke the speed record of the TGV before France got it back. Today, Europe is served by an extensive network of high-speed rail lines, and is the only place where a system is being developed at the continental scale. Indeed in many places in Europe borders are so seamless for high speed rail travel as to be hardly perceptible. The development of high-speed rail in Europe has revolutionized long distance travel, with many of what were formerly the world's busiest air corridors now being among the most popular high-speed rail routes instead. The European Union is taking a more and more active role in railroad policy, trying to unify - sometimes deliberately chosen for their incompatibility - incompatible national standards and make cross-border open access to the rail network easier. The EU also prioritizes certain rail corridors and provides funding for their improvement.

Other East Asian countries have sought to emulate the success of high-speed rail services in Japan and Europe by building networks of their own. In particular, China has been going on a building spree of new rail lines, and now boasts the longest high-speed rail network in the world, including an "international" connection to Hong Kong that was completed in 2018. Other countries have also gotten into the game: Turkey is the first country outside East Asia or Europe to have HSR, and Saudi Arabia is planning to become the first Arab country with HSR. Many other plans were canceled due to the 2008 economic crisis, or have been put on hold perhaps indefinitely. Speed records for rail vehicles are still being set and depending on what you count are either held by France (fastest wheel on rails train), Japan (fastest maglev) or a Siemens-built locomotive on German tracks (the French record is of a multiple unit, not a locomotive hauled train) which is now employed to pull Railjet of ÖBB.

One of the most expensive factors limiting speed is curve radius. Many railway lines were built in the 19th century following river valleys or other features or had to avoid encroaching on the land of certain landowners and are thus rather curvy. In mountainous areas lines were sometimes deliberately built curvy to allow heavy and underpowered steam trains to climb the slopes, sometimes with spirals where long trains would pass over themselves. Engineers in several countries were tasked with allowing trains to go faster on existing or only moderately upgraded track either to deliver HSR earlier to more people or to avoid the daunting investment of new construction. England, which had a curvy legacy network but was at the time averse to spend much on infrastructure and Italy, which has the Alps in the North and the Apennines along its spine were at the forefront of this development. Both countries saw the solution in a train tilting to decrease lateral forces, similar to what motorcyclists do. There was the question of "active tilt" i.e. the carriages being tilted by motors hydraulics and so on or "passive tilt" where the carriages would be moved by the inertia of the train entering the curve. British Rail developed the "Advanced Passenger Train" or APT the first train with active tilt in passenger service. However, the APT was plagued with teething issues, among them motion sickness experienced by journalists on a test run and thus the project was canceled and the patents sold to Italian companies. The Italians meanwhile developed a series of trains, initially with passive tilt called "Pendolino" which has become the generic name of tilting trains in many languages even though it is still trademarked. Italian tilting train technology enjoys a good reputation and is exported to the British Isles among other places. Not all tilting trains meet the common definitions of high speed rail but they are usually the fastest trains on any given route. In some countries - notably Germany - there have been problems with certain tilting trains leading to the tilting mechanism being disabled or their premature withdrawal from service.

China Railway High-speed (中国高速铁路) (CRH) – The only high-speed trains in the world that offer sleeper cabins on longer routes due to the vast distances covered. Cross-border services run via Guangzhou and Shenzhen to West Kowloon Railway Station in Hong Kong. Plans for other international routes have been announced, but no construction has started as of 2018.

Shinkansen (新幹線), also known as the bullet train. While Japan's legacy rail network is built to 1,067 mm (42.0 in) gauge, all Shinkansen lines are built to standard gauge due to the higher requirements of faster trains. The original high-speed rail service, operated by the JR companies that are the privatized successors of Japan's state railways. Trains are fast, clean and on time, but prices are higher than in Europe or other Asian countries. While the network reaches all of Japan's main islands it is low on links perpendicular to the main length of the main islands and only started to serve the very southern tip of Hokkaido in 2016 with extensions to cover most of the island planned to be opened gradually until the early 2030s.

Korea Train eXpress (한국고속철도) (KTX). The KTX is often promoted as an indigenous Korean development, though it is in truth derived from the TGV. The Seoul - Busan route in particular helped ease congestion on one of the country's busiest highways and reduce flights on one of the world's busiest flight corridors. Proposals for an undersea tunnel to Jeju are variously made due to the immense popularity of the island and the strain flights to Jeju put on domestic airport capacity. The 2018 thaw in relations with the north also makes links to or through North Korea more realistic.

Taiwan High Speed Rail (台灣高速鐵路) (THSR), built using Japanese Shinkansen technology. A single line connects the north and south of the island along its western shore. THSR has greatly reduced domestic flights. Early bird fares offer discounts up to 35% of the regular walk-up fare which is less of a spread than the difference between early bird and walkup fares in Europe but still unusual for east Asian HSR.

Turkish State Railways' Yüksek Hızlı Tren (YHT) (literally high-speed train) has two routes in operation originating in Ankara. One links to Pendik (a suburb of Istanbul on the Asian Side) via Eskişehir and the other branches off from that line to serve Konya. A tunnel under the Bosphorus will allow the YHT to extend into Europe once construction work to connect it to the national network is complete. Tickets tend to be rather affordable (e.g. 86 lira for a one-way trip from Istanbul to Konya) but trains can book out rather quickly, so you should book ahead even though prices are fixed. Plans to extend the network are underway.

Europe is the only continent with a truly international high-speed rail network, and therefore has several operators linking multiple countries together. There is a reasonable level of integration and cooperation between these companies, allowing passengers to purchase through-tickets on journeys that use more than one company and cross several borders.

Eurostar connects the United Kingdom to France, Belgium and the Netherlands via the Channel Tunnel. Major cities served: Avignon, Brussels, Lille, London, Lyon, Marseille, Paris. Services from London and Brussels to Rotterdam and Amsterdam started in April 2018, although the equivalent reverse journey (Netherlands to UK) will involve a change in Brussels for the foreseeable future due to Dutch stations not providing space for border checks. It is not clear whether Brexit will affect Eurostar operations.

The TGV also crosses borders into many of France's neighbors, namely Belgium, Germany, Italy, Luxembourg, Spain and Switzerland (where the service is known as TGV Lyria). The service between France and Germany is jointly operated by the SNCF and Deutsche Bahn, with ICE and TGV trains running on both sides of the border. A similar arrangement works between the SNCF and Spanish company Renfe for journeys between France and Spain. Major cities served outside of France: Barcelona, Basel, Brussels, Frankfurt, Geneva, Luxembourg, Milan, Munich, Stuttgart, Turin

Thalys connects France to Belgium and the Netherlands as well as Germany. Major cities served: Amsterdam, Antwerp, Brussels, Cologne, Lille, Paris, Rotterdam

The Swiss, German and Italian railways jointly run a train service with a top speed of 250 km/h (160 mph) from Frankfurt to Milan and back once daily. The service is branded as Eurocity Express by DB but shows up as a normal EuroCity in Swiss and Italian schedules. Tickets can be bought and schedules in English obtained from Deutsche Bahn. Intermediate stops include Mannheim, Karlsruhe, Basel and Bern, plus several resort towns in western Switzerland.

While several new and upgraded lines have a design speed of 250 km/h, actual maximum speed in daily operations is limited to 230 km/h, which is reached by the Austrian locomotive hauled Railjet and ICE trainsets operated by ÖBB (Austrian State Railways) and Deutsche Bahn (German State Railways). The fare structure of ÖBB is similar to DB, though sometimes walk-up fares are a bit cheaper.

Due to the country's small size, Belgium's high-speed network is centered around international services, and accordingly all high-speed services in the country are operated by foreign companies (Deutsche Bahn, Eurostar, SNCF and Thalys) rather than by the National Railway Company. Brussels is nonetheless connected domestically to Antwerp and Liege by high-speed lines.

The French national rail company SNCF operates the famous Train à Grande Vitesse (TGV) to most major cities in the country, along an extensive network of purpose-built lines (270-320 km/h) and in part along older and much slower lines. There is also a low-cost high-speed service run by the SNCF but separate to the TGV, called Ouigo, which operates from Marne-la-Vallée (near Disneyland Paris) on some routes north, west and south. Most lines connect to one of the great Paris termini on one end. The erstwhile rapid pace of new construction has slowed down considerably and President Macron has publicly questioned the need for any high speed lines beyond those already existing.

Deutsche Bahn's Intercity-Express (ICE) operates to many cities around Germany, though the network is slightly less well-developed than other European countries (but catching up fast). The older Intercity trains are capable of speeds up to 200 km/h and are not marketed as "high-speed" even though similar trains in other countries get this designation. On specific routes there are "ICE Sprinter" which only stop at major cities and are usually fast enough to be more attractive to business travelers than planes. In December 2017 a new line opened slashing travel times between Berlin and Munich from six hours to less than four which saw an enormous increase in passengers, the line carrying one million people in its first hundred days. In fact, flights from Nuremberg to Berlin are to cease in March 2019 as a direct consequence of the opening of the new line.

Italy is served by two high-speed rail companies. The Frecciarossa is run by Trenitalia, the Italian national railway company. Nuovo Trasporto Viaggiatori (NTV) is a private company, with Ferrari being one of the investors. They serve their routes with a TGV-derived train known as the Italo.

Due to its small size, high-speed rail in the Netherlands is primarily centred around international services. The Netherlands have one dedicated high-speed line and a number of improved traditional railway lines. Services are operated by Deutsche Bahn and Thalys, rather than by Nederlandse Spoorwegen. High-speed Thalys trains run between Amsterdam and Rotterdam Centraal stations, via Schiphol Airport, and across the border into Belgium. Eurostar started serving Amsterdam and Rotterdam in 2018. ICE Trains from Germany run along traditional-speed lines. There was a brief period in late 2012/early 2013 when a train under the name "Fyra" was run as the Dutch high-speed rail service, however, technical problems caused the service to be withdrawn after barely a month of service. Since then, the "Fyra" trains have been replaced by refurbished intercity cars that run on the high-speed line at a lower speed (160 km/h compared to 300 km/h on the Thalys and Eurostar). New trains running at 200 km/h top speed are expected to replace the intercity cars from 2020.

Russian Railways' Sapsan (Сапсан) has services from Moscow to St. Petersburg. The line to Nizhny Novgorod was formerly operated by Sapsan trains but now by the somewhat slower Strizh (Стриж) running at 200 km/h top speed. A few Strizh services now run all the way to Berlin. Some other lines are either under construction or planned, including the Moscow–Kazan line which potentially could be the first section of a high-speed line to Beijing.

Renfe's Alta Velocidad Española (AVE) is one of the largest systems in the world, second only to China in total length. While the economic crisis since 2008 has slowed the boom of new construction for the time-being (and the connection to Portugal has been put on hold indefinitely), Renfe has lowered prices to keep passenger numbers up. In addition to AVE, there is also Avant with top speeds up to 250 km/h. Spanish high speed rail operates on standard gauge to ensure compatibility to the French network, but there are trains capable of changing onto the broad gauge legacy network.

Switzerland, being small, compact and very mountainous, has no high-speed rail lines except for two tunnels mainly intended for freight, though it does receive ICE and TGV trains from Germany and France respectively, which make use of classic lines. The Lötschberg Base Tunnel allows trains to run at 250 km/h along its 35-km length. Similarly, the Gotthard Base Tunnel, while primarily intended for freight trains, has a design speed of 250 km/h which makes it a "high-speed" line. It shortens many trips through the Alps by half an hour and relieves freight bottlenecks, despite its short length compared to other high-speed lines. Switzerland's national railway SBB has since acquired rolling stock capable of top speeds of 250 km/h which will likely be marketed under the name "Giruno" (derived from the Romansh word for buzzard) on international routes to/from Italy using the Gotthard Base Tunnel. The train is also planned to receive certification for Germany and Austria some time after its planned entry into service late 2019.

The UK has one high-speed line, between London St Pancras station and the Channel Tunnel. Domestic services are operated on the line by Southeastern Highspeed between London and several towns in Kent. The trains, nicknamed the "Javelin", operate at 140 mph (225 km/h). Other intercity routes marketed as "high-speed" or "express" are slower, generally operating at a maximum speed of 125 mph (200 km/h). Indeed, new intercity trains being introduced on two main lines are capable of 140 mph but are limited to 125 mph due to infrastructure concerns. Although a national high-speed rail network is approved by Parliament and under development, it is not scheduled to open until 2026, with later phases opening in 2027 and 2033.

While high-speed rail services have been proposed in Canada and Australia, the popularity of private car ownership and air travel, as well as political wrangling, mean that high-speed rail is likely to remain a distant dream for the foreseeable future.

In the United States, Amtrak's Acela Express on the Northeast Corridor between Boston and Washington has trains that briefly achieve a top speed of 150 mph (240 km/h), but due to its relatively low average speed, is not universally considered a high-speed service. California High-Speed Rail (CAHSR) is under construction in California to connect the Central Valley towns of Bakersfield and Merced via Fresno, with completion expected in 2029. The privately-owned Texas Central Railway, meanwhile, is actively acquiring land to build a Shinkansen line (in partnership with Japan Rail) connecting Dallas and Houston in under 90 minutes, at a top speed of 205 miles per hour (330 km/h). Completion is optimistically expected in 2024.

India began construction of its first high speed rail line in 2017 using Japanese Shinkansen technology including standard gauge, despite the fact that Indian broad gauge is by far the most used gauge in India and Pakistan and other international connections are of limited importance.

In other parts of the world, high-speed rail links are often 'announced' as part of a larger infrastructure investment, and then quietly dropped later.

In many regards railways that run high-speed lines have taken a page out of the play book of (no frills) aviation. This means an emphasis on fast turnaround times as well as a ticketing system intended to maximize occupancy as well as revenue. As a customer, be prepared for two things: relatively low (and widely advertised) special offers for off peak trains or early booking and high walk up fares. SNCF and DB are particularly notorious for this with tickets "from" €29 or even €19, but reaching well into the triple digits when bought on the day of travel or on the train. In Britain the same holds true even for non high-speed trains.

Japan on the other hand offers relatively few discounts and comparatively high fixed prices. In South Korea, high-speed trains have fixed prices that are significantly more expensive than conventional trains, but nevertheless much more reasonable than those in Japan. In Taiwan, high-speed trains have early bird fares that give up to 35% discount off the walkup rate. This is a significantly smaller span than in France or Germany, for example, but a departure from their earlier policy of fixed prices regardless of time of booking. Japan, South Korea and Taiwan all offer rail passes that can be used only by foreign tourists, and these can be used to limit the damage if you are planning to do a lot of long distance travelling, but are generally not worth it if you plan to stick to one city or its immediate vicinity.

If the average of all tickets sold is taken, HSR tickets are similarly priced in Spain, France and Germany while being significantly more expensive in Japan. The Acela Express serving the Northeast Corridor is even more expensive (on a per km basis) than the Shinkansen.

High-speed rail in China is very expensive for the average working class Chinese, but is reasonably priced by Western standards.

Also, many countries have discount cards with an annual fee (for example, about €60). With a discount card (e.g., BahnCard in Germany) you will get a discount of 25% or 50% (depending on the card) on the fare. There are often - widely advertised - short term versions of such discount cards that may be worth it after a few trips but read the fine print carefully as they often need to be canceled in time lest they turn into a yearly subscription.

Many railways offering high-speed service have returned to a three class system that was abolished in Europe in the 1950s with the withdrawal of (old) first class and the "uptitling" of second and third class. On many high-speed trains even regular "coach" or "second" class offers more comfort than its equivalent on slower trains. But if you (or your employer) are willing to shell out top euro, you can get business class, premium class, club class or any of the various names the marketing department has come up with. Whether the extra money is worth it depends on your perception and on the different operators, but included bonuses (such as newspapers, breakfast or coffee) are usually spelled out on the website of the operator and they usually also show pictures of their "premium" seats. Various railways also have customer loyalty programs not unlike miles for airlines. Those are usually only worth it if you travel frequently with one operator, though discount cards at a low price can pay for themselves after one or two trips - if you don't forget to cancel it in time, that is.

Some operators have started customer loyalty programs not unlike those in aviation. However, unlike airlines, train operators have not yet entered wide-reaching cooperations and as such your frequent traveler status will likely only benefit you in the country the railway in question operates. One exception to this rule is Railteam, an association of the main Western and Central European railroads (Thalys, DB, SNCF, Eurostar, SBB-CFF-FFS, NS-International and NMBS/SNCB), which offers some use of lounges in major hubs, but does not for instance offer reward points to be collected for the DB loyalty program on SNCF journeys as similar alliances for airlines often do.

Statistically speaking, high-speed rail is one of the safest ways to travel. Rail travel in general has a better safety record than road travel, with car drivers being ten times more likely to die in an accident than railway passengers. In particular, dedicated high-speed rail tracks usually do not have level crossings, tend to be built and upgraded with the latest safety features, and rely on the most cutting edge technology to prevent accidents. If systems don't malfunction it is impossible for the driver to exceed the maximum permitted velocity either by accident or on purpose - in fact some high profile crashes were due to the system to prevent excessive speeds being disabled for a test run or not yet installed on an upgraded legacy line. In general rail safety systems always "fail towards the safe side" (for example a signal that's broken will mean "stop") and the special equipment for HSR is no exception to this 19th-century rule. As such, high-speed rail lines tend to have better safety records than conventional rail lines. As a testament to the safety of high-speed rail, Japan's Shinkansen has never had a fatal crash since the network began operation, not even during major earthquakes and tsunamis.

High-speed rail travel is usually regarded as an environmentally-friendly way to get around, as the carbon footprint is almost always lower than that of aviation, usually than that of driving and sometimes less than on standard rail or bus services. This comparison of "greenness" of course depends on how the electricity used is produced. The initial construction of the infrastructure also produces noticeable environmental effects, which serves to complicate such comparisons. Most rail companies draw their electricity from a combination of railway only power plants and the general grid. Due to various technical and economic considerations railway power plants are often hydro-power, nuclear or coal fired thermal plants with wind, solar and gas fired plants historically playing marginal roles. However, due to increasing costs of fuels and in order to market rail travel as "green" more and more railway companies strive to increase their share of renewable energy. Countries like Sweden or Switzerland historically supply a lot of their railway electricity through hydropower, while France relies on nuclear energy. Germany and China rely a lot on coal, but both have heavily invested in renewable energies since the turn of the millennium.

Magnetic levitation, or maglev, trains have the potential to travel at speeds in excess of 600 kilometres per hour (370 mph), largely due to the reduced friction from levitating above the track. There are only six in operation, all in either Japan, South Korea or China, and most operate at low speeds of around 100 kilometres per hour (62 mph) as part of an intra-city public transit system. The most notable system and the only high speed one in commercial operation is the Shanghai maglev (上海磁浮), which makes the 30.5 kilometres (19.0 mi) journey from Shanghai Pudong International Airport to Longyang Road near Shanghai's city center, hitting a top speed of 431 kilometres per hour (268 mph), although the average speed is 265 kilometres per hour (165 mph).

No intercity maglev lines are in operation, though Japan is planning to open a maglev Shinkansen line from Tokyo to Nagoya by 2027.